atoi is a standard function. But itoa is not. Why?

c function posix standards itoa
Pavan Manjunath picture Pavan Manjunath · Apr 15, 2012 · Viewed 12k times · Source

Why this distinction? I've landed up with terrible problems, assuming itoa to be in stdlib.h and finally ending up with linking a custom version of itoa with a different prototype and thus producing some crazy errors.

So, why isn't itoa not a standard function? What's wrong with it? And why is the standard partial towards its twin brother atoi?

Answer

CB Bailey picture CB Bailey · Apr 15, 2012

No itoa has ever been standardised so to add it to the standard you would need a compelling reason and a good interface to add it.

Most itoa interfaces that I have seen either use a static buffer which has re-entrancy and lifetime issues, allocate a dynamic buffer that the caller needs to free or require the user to supply a buffer which makes the interface no better than sprintf.

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